This application is based on Japanese Patent Application No. 11-288032 filed Oct. 8, 1999, the contents of which are incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a control apparatus for controlling a hybrid automotive vehicle, and more particularly to technologies for reducing a control delay and a shock upon switching of an operating mode of such a hybrid vehicle from a neutral mode to a drive mode.
2. Discussion of Related Art
There is known a hybrid automotive vehicle including an internal combustion engine, an electric motor, a transmission, and a clutch device disposed between the internal combustion engine and electric motor and the transmission. Such a hybrid vehicle has an engine drive mode in which a drive force generated by the internal combustion engine is selectively transmitted to the transmission through the clutch device, a motor drive mode in which a drive force generated by the electric motor is transmitted to the transmission through the transmission, a regenerative braking mode in which the electric motor is driven by a kinetic energy of the vehicle to produce a regenerative braking torque, and an engine-start mode in which the internal combustion engine is started by the electric motor. An example of such a hybrid vehicle is disclosed in JP-A-11-127502.
When the operating mode of the known hybrid vehicle indicated above is switched from the neutral mode to the drive mode (the motor drive mode or engine drive mode), the clutch device is brought to its engaged state only after the clutch elements have been synchronized, so that the drive force can be smoothly transmitted to the electric motor or internal combustion engine to the transmission, without an engaging shock of the clutch device.
The synchronization of the clutch elements upon switching of the operating mode requires and causes some delay time before the completion of the engaging action of the clutch device, making it difficult to achieve a rapid switching of the operating mode with a high operational response.
The prevent invention was made in view of the background prior art discussed above. It is therefore an object of the present invention to provide a control apparatus for controlling a hybrid automotive vehicle, which control apparatus assures a high operational response upon switching of the operating mode of the vehicle.
The above object may be achieved according to any one of the following modes of the present invention, each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate and clarify possible combinations of elements or technical features. It is to be understood that the present invention is not limited to the technical features or any combinations thereof which will be described for illustrative purpose only. It is to be further understood that a plurality of elements or features included in any one of the following modes of the invention are not necessarily provided all together, and that the invention may be embodied without some of the elements or features described with respect to the same mode.
(1) A vehicle control apparatus for controlling a hybrid vehicle of a type which comprises a first drive power source, a second drive power source, and a power transmitting system including a transmission and a planetary gear device having a first rotary element connected to the first drive power source, a second rotary element connected to the second drive power source and further connected to the transmission through a first clutch, and a third rotary element connected to the transmission through a second clutch, the first clutch including one pair of friction members connected to the first rotary member and the transmission, respectively, the second clutch including one pair of friction members connected to the third rotary element and the transmission, respectively, the vehicle control apparatus further comprising:
neutral-mode determining means operable when the first and second clutches are both placed in a released state, for determining whether the power transmitting system is placed in a first neutral state or a second neutral state, depending upon which one of the first and second clutches is to be engaged when a driving of the hybrid vehicle in a vehicle drive mode is subsequently initiated;
first synchronizing means operable when the neutral-mode determining means has determined that the power transmitting system is placed in the first neutral state, for synchronizing speeds of the one pair of friction members of the first clutch with each other; and
second synchronizing means operable when the neutral-mode determining means has determined that the power transmitting system is placed in the second neutral state, for synchronizing speeds of the one pair of friction members of the second clutch with each other.
In the vehicle control apparatus constructed according to the above mode (1) of this invention, the first synchronizing means is operated when the neutral-mode determining means has determined that the power transmitting system is placed in the first neutral state. The first synchronizing means is adapted to synchronize the speeds of the friction members of the first clutch which is to be engaged when the driving of the vehicle in a drive mode is subsequently initiated while the power transmitting system is placed in the first neutral state. The second synchronizing means is operated when the neutral-mode determining means has determined that the power transmitting system is placed in the second neutral mode. The second synchronizing means is adapted to synchronize the speeds of the friction members of the second dutch which is to be engaged when the driving of the vehicle is subsequently initiated while the power transmitting system is placed in the second neutral state. Owing to the speed synchronization of the friction members of the first or second clutch which is to be engaged upon subsequent initiation of the vehicle driving in an appropriate drive mode while the power transmitting system is placed in the corresponding first or second neutral state, the appropriate drive mode can be rapidly established with a high operational response, and with a reduced shock due to an engaging action of the appropriate clutch.
(2) A vehicle control apparatus according to the above mode (1), wherein the first synchronizing means synchronizes the speeds of the one pair of friction members of the first clutch, by controlling an operating speed of the second drive power source.
(3) A vehicle control apparatus according to the above mode (1) or (2), wherein t he second synchronizing means synchronizes the speeds of the one pair of friction members of the second clutch, by controlling an operating speed of the second drive power source.
In the vehicle control apparatus according to the above mode (2) or (3), the speeds of the friction members of the first or second clutch are synchronized by the corresponding first or second synchronizing means by utilizing a rotary motion of the second drive power source, rather than a rotary motion of the first drive power source, so that the synchronization of the clutch can be achieved over a comparatively wide range of the operating speed of the input shaft of the transmission.
(4) A vehicle control apparatus according to any one of the above modes (1)-(3), wherein the hybrid vehicle has a front wheel and a rear wheel, and further comprises a third drive power source, and wherein one of the front and rear wheels is connected to the first drive power source and the second drive power source through the transmission, and the other of the front and rear wheels is connected to the third drive power source, the third drive power source generating a signal representative of a rotating direction of the other wheel, while the third drive power source is not operated to apply a driving torque to the other wheel, the first synchronizing means synchronizing the speeds of the one pair of friction members of the first clutch, on the basis of the rotating direction of the other wheel represented by the signal.
(5) A vehicle control apparatus according to any one of the above modes (1)-(4), wherein the hybrid vehicle has a front wheel and a rear wheel, and further comprises a third drive power source, and wherein one of the front and rear wheels is connected to the first drive power source and the second drive power source through the transmission, and the other of the front and rear wheels is connected to the third drive power source, the third drive power source generating a signal representative of a rotating direction of the other wheel, while the third drive power source is not operated to apply a driving torque to the other wheel, the second synchronizing means synchronizing the speeds of the one pair of friction members of the second clutch, on the basis of the rotating direction of the other wheel represented by the signal.
In the vehicle control apparatus according to the above mode (4) or (5), the first or second synchronizing means synchronizes the speeds of the friction members of the corresponding first or second clutch, on the basis of the detected direction of rotation of the wheel connected to the third drive power source. Accordingly, the operating mode of the vehicle can be switched from the neutral state to the appropriate vehicle drive mode, with high stability, irrespective of whether the vehicle is driven in the forward or reverse direction.
(6) A vehicle control apparatus according to any one of the above modes (1)-(5), wherein a drive force generated by the second drive power source is transmitted to the transmission through the first clutch placed in its engaged state, during the driving of the hybrid vehicle in the vehicle drive mode when the driving in the vehicle drive mode is initiated while the first drive power source is at rest, and a drive force generated by the first drive power source is transmitted to the transmission through the second clutch placed in its engaged state, during the driving of the hybrid vehicle in the vehicle drive mode when the driving in the vehicle drive mode is initiated while the first drive power source is in operation, the neutral-mode determining means includes:
operation determining means for determining whether the first drive power source is in operation or at rest;
first-neutral-state determining means for determining that the power transmitting system is placed in the first neutral state, when the operation determining means has determined that the first drive power source is at rest; and
second-neutral-state determining means for determining that the power transmitting system is placed in the second neutral state, when the operation determining means has determined that the first drive power source is in operation.
In the apparatus according to the above mode (6), the neutral-mode determining means, which is operated while the first and second clutches are both placed in the released state, is arranged to determine whether the power transmitting system is placed in the first neutral state or in the second neutral state, depending upon whether the first drive power source is at rest or in operation. This arrangement assures accurate determination as to whether the power transmitting system in the first neutral state or in the second neutral state. When the driving of the vehicle is initiated in the first neutral state in which the first drive power source is at rest, the first clutch is engaged to establish the vehicle drive mode, so that the drive force is transmitted from the second drive power source to the transmission through the engaged first clutch. When the driving is initiated in the second neutral state in which the first drive power source is in operation, the second clutch is engaged to establish the vehicle drive mode, so that the drive force is transmitted from the first drive power source to the transmission through the engaged second clutch.
(7) A vehicle control apparatus according to the above mode (6), wherein the hybrid vehicle has an operator-controlled member having a least one vehicle-drive position in which the hybrid vehicle is driven by at least one of the first drive power source and the second drive power source, and at least one non-vehicle-drive position in which the first and second clutches are placed in the released state and the hybrid vehicle is driven by none of the first drive power source and the second drive power source, said neutral-mode determining means being operable when the operator-controlled member is placed in the non-vehicle-drive position.
(8) A vehicle control apparatus according to any one of the above modes (1-7), wherein the first drive power source is an internal combustion engine, and the second drive power source is a motor/generator.
(9) A vehicle control apparatus according to the above mode (4) or (5), wherein the first drive power source is an internal combustion engine, and the second and third drive power sources are a first motor/generator and a second motor/generator, respectively.